Resistance shunt-circuit breaker



Mar h 1929- w. M. AUSTIN RESISTANCE SHUNT CIRCUIT BREAKER Filed July 5, 1926 ATTORNEY Patented Mar. 19,

UNITED-*STATES PATENT OFFICE.

WALTER M. Austin, or swrssvarn, PENNSYLVANIA, AssIeno'R .ro wns'rmenousn nnnc'rnica manurac'runme COMPANY, A conrormrron or PENNSYLVANIA.

Basis-ration SHUNT-CIRCUIT BREAKER.

Application iled July 3,

My invention relates to electrical protective apparatus and particularly to transformer switching equipment.

One object of myinvention is to provide a switching equipment for transformers that shall initially limit the amount of current traversing a transformer winding.

Another object of my invention isto pro magnitude of such currents may be sufliciently great to injure the transformer windmgs.

Even if the transient starting. current is not great enough to/damage any part of the transformer. it may easily be great enough to trip the circuit interrupter, thus opening the circuit at the instant of closing, unless the tripping point is set too high to be of any use in protecting the transformer against subsequent abnormal loads.

Accordingly, I propose to connect a resistor in series relation with the primary winding of the transformer during an initial closing operation of a circuit interrupter and to shunt-clrcmt the reslstor during the final closing operation of the circuit interrupter, In the accompanying drawings, Fig. 1 is a view, in perspective, of a circuit interrupter embodying my 1nvent1on, and

Fig. 2 is a diagrammatic viewof circuitsand apparatus embodying my invention.

My invention comprises, in general, a circuit interrupter 1 that is provided with two independent circuit-interrupting units 2 and 3 that are mounted on a common panel 4:, on which is also mounted an auxiliary contact member 5 that is connected to one end of a resistor 6. The other end of the resistor 6 is connected to a stationary contact member 7 of the circuit-interrupter unit 3 and, through the latter, to the sup 1y circuit 18. An elec-' trical transformer 8 as its primary winding 9 connected between the lower stationary con- 1926. Serial No. 120,467.

tact member of circuit-interrupter units 2 and 3.

The circuit-interrupter unit 2 may be of any preferred type, comprising a stationary contact member 11 mounted on the panel 4, a movable contact member 12, the usual arcing-tip 13, atrip coil 14 and an operating handle 15. J

The circuit-interrupter unit 3 differs from the circuit-interrupter unit 2, only in that the arcing contact member 16 is of suificient width to engage the contact member 5 and a stationary contact member 7., a The contact member 5 is resiliently mounted on the panel 4 and extends outwardly farther than the stationary contact members 7 and 11. The resistor 6 is connected between the stationary contact member 7 of the circuit-interrupter unit 3 and the auxiliary contact member 5.

A supply circuit 18 is provided for energizing the transformer 8. e

When it is desired to connect the transformer 8 to the supply circuit 18, an operator takes hold of the handle 15 of the circuit-interrupter unit 2, and closes it. He then takes hold of the operating handle 15 of the circuit-interrupter unit 3 and starts to close the latter. During the first part of the closing movement, the movable contact member 12 engages the contact members 5 and 17, there-' byclosing the circuit through the primary winding 9 of the transformer 8, with the re sister 6 inserted in circuit therewith, the result being that the amount 'of current traversing the primary winding 9 is limited to a safe value.

Further closing movement of the circuitinterrupter unit 3 completes the engagement oftlie movable contact member 12 and the stationary contact member 7, whereby the resistor 6 is shunt-circuited, and the winding 9 is connected directly to the supply circuit 18. The eriod of time required to move the movab e contact member 12 from its position of engagement with the contact member '5 to its engagement with the stationary contact member 7 is sufficiently great to permit the transformer 8 to become stabilized Accordingly, I have provided a circuit interrupter that is adapted for use in switching systems for transformers where it is desired to control the initial surge of current traversing the primary winding of a transformer by inserting a resistor in series relation to the transformer winding and then shunt-circuiting the resistor during the final closing operation of the circuit interrupter.

It is to be understood that such changes may be made in the number, disposition and connections of the component parts of my invention as may fall within the scope of the appended claims.

I claim as my invention:

1. The combination, in a circuit interrupter having main and auxiliary stationary and movable contact members, of a separate resiliently supported contact member adapted to enga e the movable auxiliary contact member before the said movable auxiliary contact member comes into engagement with the stationary auxiliary contact member.

2. The combination, in a circuit interrupter having main and auxiliary stationary and movable contact members, of a separate resiliently supported contact member adapted to engage the movable auxiliary contact member before the said movable auxiliary contact member comes into engagement with the stationary auxiliary contact member, said separate contact member becoming disengaged from the movable contact member only after its disengagement from the stationary auxiliary contact member.

3. The combination with the stationary and movable carbon contact members of a circuit interrupter, of a separate carbon contact member resiliently mounted to-so protrude beyond the statlonary carbon contact member that the movable carbon contact member will come into engagement therewith 5;

before engaging the said stationary carbon contact member.

4. The combination with the stationary and movable carbon contact members of a circuit interrupter, of a separate carbon contact member resiliently mounted to so protrude beyond the stationary carbon contact member that the movable carbon contact member Will come into engagement therewith before engaging the said stationary carbon contact member and Will be released there from only after its disengagement from the stationary carbon contact member.

5. The combination, in a circuit interrupter having main and auxiliary stationary contact members, of a separate resiliently mounted stationary contact member, a main bridging member, and an auxiliary movable contact member that successively engages the resiliently mounted contact member and the stationary auxiliary contact member.

In testimony whereof, I have hereunto subscribed my name this 24th day of June, 1926.

WALTER M. AUSTIN. 

